The present invention is generally directed to imaging processes with cold pressure fixable toner compositions, and more specifically the present invention is directed to electrophotographic and ionographic imaging processes with single componenet cold pressure fixable toner compositions possessing a resistivity of from about 10.sup.4 to about 10.sup.7 ohm-cm. Accordingly, in an embodiment of the present invention there are provided the aforesaid imaging processes with cold pressure fixable toner compositions comprised of resin particles, a wax component, magnetite, release fluids such as silicone fuser oils, and conductive particles, such as carbon black, on the surface thereof, which toners are fixable at from about 200 to 400 pounds per linear inch. Also, the toners of the present invention are useful for permitting the development of images in electrophotographic and ionographic imaging systems, inclusive of electrostatic imaging processes wherein pressure fixing, especially pressure fixing in the absence of heat, is selected.
Cold pressure fixing processes are known. These processes have a number of advantages in comparison to heat fixing, primarily relating to the requirements for less energy since the toner compositions used can be fused at room temperature. In some of the prior art processes substantial image smearing can result from the high pressures required. Additionally, the cold pressure fixing toner compositions of the prior art have other disadvantages in that, for example, these compositions when used for development cause in some instances images with high gloss that are of low crease resistance.
Representative prior art includes U.S. Pat. Nos. 4,430,408, which illustrates cold pressure fixable toner compositions with fluorine-modified alkyl siloxane dispersed therein; 4,514,485 wherein there is disclosed magnetic toner particles coated with a low surface energy resin, reference column 2, lines 22 to 34; 4,568,625, which discloses a developer which contains a silicone oil which has an amine on the side chain thereof, reference column 7, lines 41, to column 2, line 62; 4,517,272; 4,585,723; 4,618,556; and 4,640,881.
Of particular interest in U.S. Pat. No. 4,517,272, which discloses the reduction of hollow character defects and electrostatically transferred dry toner images by the selection of an electrostatic dry toner composition comprising a binder powder, a low surface energy liquid such as a silicone oil, and a carrier, reference column, 1, beginning at line 61. Examples of silicone oils include those as illustrated in column 3, line 6. Also, apparently other liquids can be selected, see column 3, beginning at line 20. In contrast, the present invention is directed to cold pressure fixable toners that fix at pressures of, for example, 200 to 400 pounds per inch.
With further reference to the prior art, there is disclosed in U.S. Pat. No. 4,307,169 microcapsular electrostatic marking particles containing a pressure fixable core, and an encapsulating substance comprised of a pressure rupturable shell, which shell is formed by an interfacial polymerization. One shell prepared in accordance with the teachings of this patent is a polyamide obtained by interfacial polymerization. In the '169 patent, it is indicated that when magnetite or carbon black is selected they must be treated in a separate process to prevent migration thereof to the oil phase.
Moreover, there is disclosed in U.S. Pat. No. 4,407,922 interfacial polymerization process for pressure sensitive toner compositions comprised of a blend of two immiscible polymers selected from the group consisting of certain polymers as a hard component, and polyoctadecylvinylether-co-maleic anhydride as a soft component.
Additionally, illustrated in U.S. Pat. No. 4,758,506, entitled Single Component Cold Pressure Fixable Encapsulated Toner Compositions, are single component cold pressure fixible toner compositions, wherein the shell selected can be prepared by an intefacial polymerization process. A similar teaching is present in copending application U.S. Ser. No. 718,676, now abandoned, the disclosure of which is totally incorporated herein by reference, directed to single component magnetic cold pressure fixable toner compositions. In the aforementioned application, the core can be comprised of magnetite and a polyisobutylene of a specific molecular weight encapsulated in a polymeric shell material generated by an interfacial polymerization process. More specifically, there is illustrated in the aforementioned copending application cold pressure fixable magnetic single component developers with small amounts of carbon black and large amounts of magnetite.
Accordingly, there is a need for improved imaging processes with contamination free cold pressure fixable toner compositions useful in electrophotographic, and ionographic imaging processes. Also, there is a need for imaging processes with single component cold pressure fixable toner compositions of a conductivity of from about 10.sup.4 to about 10.sup.7 ohm-cm. There is also a need for contamination free ionographic processes with cold pressure fixable toner compositions containing release fluids such as silicone oils and certain resin particles. Moreover, there is a need for ionographic imaging and printing processes, such as those encompassed by the commercially available Delphax 4060.TM. printer, which compositions contain therein silicone oils, and thereon conductive particles such as carbon black. There is also a need for single component toner compositions that are pressure fixable at from about 200 to about 400 pounds per linear inch. Additionally, there is a need for imaging processes wherein images of excellent quality with substantially no background deposits are consistently obtained. Another need of the present invention resides in obtaining pressure fixable toners with an average particle diameter of from about 10 to about 30 microns, which toners can be obtained in high yield by the utilization of known micronization apparatuses; and pressure fixable toners, which do not agglomerate at temperatures of up to 150.degree. F., that is a pressure fixable toner that exhibits excellent blocking properties.
Furthermore, there is a need for pressure fixable toners, and imaging and printing methods utilizing such toners wherein the toners exhibit excellent flow properties, particularly in developer housings such as those as illustrated in U.S. Pat. No. 4,692,017, the disclosure of which is totally incorporated herein by reference.